Aeroplane.



E. -F. GALLAUDET.

AEROPLANE. I APPLICATION H LED APR. 4, I914.

1,203,558. Patnted Oct. 31,1916.

2 SHEETS-SHEET I Inventor:

'Atty E. F. GA LLAUDET.

AEROPLANE.

Patented 001;. 31, 1916.

. A Inventor:

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Atty

EDSON F. GALLAUDET, 0F NORWICH, CONNECTICUT.

AEROPLANE.

Specification of Letters Iatent.

Patented Oct. 31, 1916.

Application filed Apri14, 1914. Serial No. 829,472.

To all whom it may concern:

Be it known that I, EnsoN F. GALLAUDET, a citizen of the United States, and a resident of the town of Norwich, in the county of New London and State of Connecticut, have invented certain new and useful Improvements in Aeroplanes, of which the following is a specification.

This invention relates to flying machines of the aeroplane type, and more particularly to the construction of the outer end portions of the wings or main sustaining planes of such machines. i

It has long been known by those skilled in the art of aeronautics that a flying machine rovided with dihedral wings and having a ow center of gravity will maintain its lateral equilibrium in undisturbed air, but such machines have never come into general use because of the dangerous oscillation to which they are subject when the conditions of the air become much disturbedr It is also well understood that, While the lifting or supporting power, of the wings depends mainly upon their surface areaand' the reaction between the air and their lower surfaces, due both to the angle and velocity of the impact, the moment of inertia of the machine about its fore and aft axis varies according to the square of the distance of the point of the machine from the axis.

Consequently, it is a disturbed condition ofthe air which unbalances the pressure upon the outer ends of the wings, or portions thereof at some distance from the body,

which is most dangerous to the lateral stability of the machine. Furthermore, conditions whichwill have no opreciable effect when the machine is in full flight, both be- 1 cause the rapid motion of the mtchine tends stantially neutralize the effect of changes inthe air pressure thereon and to automatically The invention comprises, as its principal feature, a permanent warping of the. outer ends of the wings, on opposite sides of the machine, so that their tips will stand at a negative angle of incidence, presenting their upper surfaces to the action of the air, and, secondary thereto, making flexible the upwardly inclined rear sections of the tips and the downwardly inclined rear sections of the adjacent portions of the wings. Thus, the reaction between the air and the tips will tend to depress the outer ends of the wings, and such action upon a relatively small surface at the tips will, because of the long lever arm upon which it acts, substantially counterbalance the disturbing action of the air upon the under side of the adjacent portion of the wings without seriously im airing the lifting or sustaining power 0 the wings as a whole. And because of their flexibility, the rear sections of the tips and nection with the accompanying drawings, in

which Figure 1 is a plan view of a novel aerohydroplane, also of my invention, with a part of the upper surface covering 'of one wing cut away toshow the construction of the outer end portion thereof, 'in which are embodied the features of the present invention; Fig. 2, a front elevation of the same machine; and Figs. 3 and 4 diagrammatic representations, on an enlarged scale, of the shape of the wing and tip on the section lines 3 3 and 4 4, respectively, of Fig. 1.

Referringto the drawings, the machine thereillustrated, by way of example, com- I prises, as its principal parts, a pisciform body B, provided with the usual fixed tail planes F F, hinged elevating .planesE E, and rudder R, and, suitably mounted thereon, the dihedral wings W W, and propellers P P. The framework of the wings is formed with the usual tubular transverse spars 1, 2, and 3 and front and rear edge pieces 4 and 5, which edge pieces are curved, as shown, to give a tapering rearward extension to the outer portions of the wings. The fore and aft ribs 6 of the main portions of the wings, which are suitably mounted upon the spars and connected at their ends to the edge pieces, are curved downwardly at their rear ends, while the rearwardly diverging diagonal ribs 7 of the tips, which are suitably secured to the rear spar and the edge pieces with the outermost rib extending forward and secured to the middle spar to give greater strength, are curved upwardly at their rear or outer ends. The downward curvature of the three or four outer ribs 6 gradually decreases until the outermost of these ribs is substantially straight at its rear end and the upward curvature of the ribs 7, which is small in the case of the innermost rib, reaches a maximum in the two longer middle ribs, and decreases again in the outermost rib; while all of the ribs are tapered from front to rear so as to render them flexible, and more especially so from points in or approximate to the broken line 00 at (Fi 1) backward to their extreme rear ends. his framework is covered above and below with the usual or any suitable surface covering 8.

The wing structure thus formed has, on each side of the machine, a permanent warp in its outer end portion which gradually converts the positive angle of incidence of its main portion into a negative angle at the tip, and the rear edge, because of the gradually increasing length of the free tapering ends of the ribs, is increasingly flexible from near the outer end to and at the tip.

The action of the wings in automatically maintaining the lateral stability of the machine will be apparent from the explanation heretofore given. An unb-alancin g of the air pressure upon the inner portions of the wings on opposite sides of the machine, from the body out to a point indicated by the broken line y y (Fig. 2), for example, has

little effect upon the equilibrium of the machine, as already stated, because of the shortness of the leverage relative to the weight and momentum of the machine. The disturbing elfect of an unbalanced air pressure upon the wings outside such point is, however, eliminated or reduced to a minimum, since the pressure agains the under surface of the wing out to the point-indicated by the broken line a a (Fig. 2), where the angle of incidence changes from positive to negative, is counter-balanced by the pressure against the upper surface of the tip, the small area of which is offset by the longer lever arm upon which it acts. Thus,

the wings will be held in normal position and the equilibrium of the machine be maintained however disturbed the condition of the air may be. It is also evident that, because of their relatively small area, the effect of the'tips upon the lifting or supporting powerof the wings as a whole will be insignificant, and especially so when the machine is in full flight since the tips which normally, and also when the machine is moving slowly and their balancing action is most needed, present larger angles of incidence than the adjacent portions of the wings, will, by reason of the greater flexibility of their ribs, yield more readily and so conform more nearly to the stream lines of the air when the machine is in full flight.

W'hile T have here illustrated and described my invention as embodied in the dihedral wings of an aero-hydroplane and in the specific form which I now consider to be the best for applying its principle, it is to be understood both that it may be used in flying machines of other types, whether monoplane or multiplane and whatever may he the form of the wings, and that it may be variously modified in its several features and details of construction, within the scope of the appended claims, without departing from the spirit or sacrificing the advantages thereof.

What I claim as new, and desire to secure by Letters Patent, is

1. lln a flying machine, a rigidly mounted integral wing structure in which the main portions of the wings, on opposite sides of the machine, are concave below and extend outwardly without forward projection at substantially right angles to the fore and aft axis of the machine and near their outer ends are curved rearwardly and permanently warped to provide rearwardly projecting flexible tips, of approximately one-fifth of the length of the wing and of relatively smaller surface area, concave above and yieldingly presenting a negative angle of incidence adapted to automatically counteract unbalanced air pressures upon the under surface of adjacent portions of the wings.

2. In a flying machine, a rigidly mounted integral wing structure in which the wings, concave below, extend outwardly on opposite sides of the machine without forward projection and substantially at right angles to its fore and aft axis and near their outer ends are curved rearwardly with an increasingly flexible trailing edge and terminate in tapering and rearwardly projecting flexible tips of relatively short length and smaller surface area which, concave above, are permanently but yieldingly flexed to a negative angle of incidence and are entirely automatic in their action.

3. In a flying machine, a rigidly mounted integral wing structure in which the wings automatic in their action.

4. In a flying machine, a dihedral wing structure in which the rigidly mounted integral wings, set at a dihedral angle, are concave below and extend outwardly and upwardly on opposite sides of the machine at substantially right angles to its fore and aft axis for the main portion of their length and near their integral outer ends are permanently warped to provide flexible tips of relatively short length and relatively smaller surface area concave above and yieldingly presenting a negative angle of incidence.

5. In a flying machine, a dihedral wing structure in which the wings, set at a dihedral angle, are concave below and extend outwardly and upwardly on opposite sides of the machine at substantially right angles to its fore and aft axis for the main portion of their length and near their outer ends are curved rearwardly with an increasingly flexible trailing edge and permanently warped to provide tapering and rearwardly projecting tips of relatively short length andsmaller surface area concave above and yieldingly presenting a negative angle of incidence.

6. In a flying machine, a dihedral wing structure in which the lower surfaces of the inner ends of the two wings are extended and joined below the .body of the machine to provide a central supporting and planing surface and their outer ends are permanently warped to provide flexible tips of relatively short length and relatively smaller surface area yieldingly presenting a negative angle of incidence.

7. In a flying machine, a dihedral wing structure in which the lower surfaces of the inner ends of the two wings are extended and joined below the body of the machine to provide a central supporting and planing surface and their outer portions are rearwardly curved and terminate in outwardly and rearwardly projecting flexible tips of relatively small surface area permanently but yieldingly Warped to a negative angle of incidence and adapted to automatically counteract unbalanced air pressures upon the under surface of adjacent portions of the wings.

8. In a flying machine, a wing structure consisting of a framework and upper and lower surface covering, the said framework comprising as elements thereof a spar secured to the body of the machine and ex tending at substantially right angles to its fore and aft axis approximately to the outer end of the wing, front and rear edge pieces,, and a series of ribs, mounted upon the spar and connected together at their front and rear ends by the edge pieces, which are convex above and concave below through the main portion of the wing and then gradually change and become concave above and convex below at the tip so as to provide a permanently warped outer portion and a tip of relatively small area presenting a negative angle of incidence. j

9. In a flying machine, a wing structure consisting of a framework and upper and lower surface covering, the said framework comprising as elements thereof a spar secured to the body of the machine and extending at substantiallyri ht angles to its fore and aft axis approximately to the outer'end of the wing, front and rear edge pieces flexible at their outer ends, and a series of ribs, mounted on the spar and connected at their front and rear ends by the edge'pieces, V

which near the outer end of the wing are progressively shorter in front and longer and more flexible to the rear of the spar andare shaped and mounted to provide a warped outer portion having a flexible trailing edge and terminating in a rearwardly and outwardly projecting tip normally presenting a negative angle of incidence.

10. In a flying machine, a dihedral wing structure consisting of a framework and upper and lower surface covering, the said framework comprising as elements thereof a spar which is secured to the framework of the machine and extends outwardly there-, from, on opposite sides, at substantially right angles to its fore and aft axis and at an upward inclination approximately to the outer ends of the wings, a series of ribs which are mounted on the spar and are curved and flexible at their rear ends behind the spar, the curvature gradually changing near the outer ends from a downward curvature through the main central portions of the wings to an upward curvature at the tips and the flexibility gradually increasing outwardly toward the tips, and flexible fore and aft edge pieces which respectively coninclination approximately to the outer ends opposite sides at substantially right angles to its fore and aft axis and at an upward Which respectively connect the front and rear ends of the ribs, the rear edge pieces being flexible throughout the outer portions of the Wings.

Boson r. GALLAUDET.

In the presence of MAY FREVERT, WM. B. WHITNEY. 

